f2c7c3c7c7
instruction the key points to is deleted Use weak value handles for both the key and the value. The entry is invalid if either value handle is null. This fixes an assertion failure in BasicAAResult::alias that is caused by UnderlyingObjCPtrCache returning a wrong value. I don't have a test case for this patch that fails reliably. rdar://83984790
88 lines
2.8 KiB
C++
88 lines
2.8 KiB
C++
//===- ProvenanceAnalysis.h - ObjC ARC Optimization -------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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/// \file
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///
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/// This file declares a special form of Alias Analysis called ``Provenance
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/// Analysis''. The word ``provenance'' refers to the history of the ownership
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/// of an object. Thus ``Provenance Analysis'' is an analysis which attempts to
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/// use various techniques to determine if locally
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///
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/// WARNING: This file knows about certain library functions. It recognizes them
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/// by name, and hardwires knowledge of their semantics.
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///
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/// WARNING: This file knows about how certain Objective-C library functions are
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/// used. Naive LLVM IR transformations which would otherwise be
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/// behavior-preserving may break these assumptions.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
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#define LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/IR/ValueHandle.h"
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#include <utility>
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namespace llvm {
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class AAResults;
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class DataLayout;
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class PHINode;
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class SelectInst;
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class Value;
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namespace objcarc {
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/// This is similar to BasicAliasAnalysis, and it uses many of the same
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/// techniques, except it uses special ObjC-specific reasoning about pointer
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/// relationships.
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///
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/// In this context ``Provenance'' is defined as the history of an object's
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/// ownership. Thus ``Provenance Analysis'' is defined by using the notion of
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/// an ``independent provenance source'' of a pointer to determine whether or
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/// not two pointers have the same provenance source and thus could
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/// potentially be related.
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class ProvenanceAnalysis {
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AAResults *AA;
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using ValuePairTy = std::pair<const Value *, const Value *>;
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using CachedResultsTy = DenseMap<ValuePairTy, bool>;
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CachedResultsTy CachedResults;
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DenseMap<const Value *, std::pair<WeakVH, WeakTrackingVH>>
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UnderlyingObjCPtrCache;
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bool relatedCheck(const Value *A, const Value *B);
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bool relatedSelect(const SelectInst *A, const Value *B);
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bool relatedPHI(const PHINode *A, const Value *B);
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public:
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ProvenanceAnalysis() = default;
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ProvenanceAnalysis(const ProvenanceAnalysis &) = delete;
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ProvenanceAnalysis &operator=(const ProvenanceAnalysis &) = delete;
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void setAA(AAResults *aa) { AA = aa; }
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AAResults *getAA() const { return AA; }
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bool related(const Value *A, const Value *B);
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void clear() {
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CachedResults.clear();
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UnderlyingObjCPtrCache.clear();
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}
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};
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} // end namespace objcarc
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} // end namespace llvm
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#endif // LLVM_LIB_TRANSFORMS_OBJCARC_PROVENANCEANALYSIS_H
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